The White-bellied Sea-eagle (Haliaeetus leucogaster), also known as the White-bellied Fish-eagle or White-breasted Sea Eagle, is a large bird of prey in the family Accipitridae which also includes many other diurnal raptors such as kites, buzzards and harriers.

It is resident from India through southeast Asia to Australia on coasts and major waterways. This large eagle is very distinctive. The adult has white head, breast underwing coverts and tail. The upperparts are grey and the black underwing flight feathers contrast with the white coverts. The tail is short and wedge-shaped as in all Haliaeetus species.

Taxonomy

The White-bellied Sea Eagle was first described by the German naturalist Johann Friedrich Gmelin in 1788. Its specific epithet derived from the Ancient Greek leuco- 'white' and gaster 'belly'. Its closest relative is the little-known Sanford's Sea-eagle of the Solomon Islands. These form a species pair, and as usual in sea eagle species pairs, as opposed to the dark-headed Sanford's, the White-bellied Sea-eagle has a white head. Talons, bill, and eyes are dark as in all Gondwanan sea eagles. This species pair has at every age at least some dark colouration in its tail, though this may not always be clearly visible in this species. Although they differ much in appearance and ecology, their ancestors diverged less than one million years ago (Wink et al., 1996).

Description Juvenile White-bellied Sea-eagle (Haliaeetus leucogaster) over the Derwent River, Hobart, Tasmania, Australia

The White-bellied Sea-eagle is one of the largest raptors in Southeast Asia, and the second largest bird of prey in Australia after the Wedge-tailed Eagle, Aquila audax, which stands up to 1 m.

The sea eagle is white on the head, rump and underparts and dark grey on the back and wings. In flight the black flight feathers on the wings are easily seen when the bird is viewed from below. The large, hooked bill is grey with a darker tip, and the eye is dark brown. The legs and feet are cream-white, with long black talons (claws). The sexes are similar. Males are 70-80 cm (28-32 in) and weigh 1.8-3 kg (4-6.6 lb). Females are slightly larger, at 80-90 cm (32-36 in) and 2.5-4.5 kg (5.5-10 lb). The wingspan is about 2 m. They soar on thermals holding their wings in a 'V' shape, unlike other raptors who hold them horizontally.

Young Sea-eagles are brown when juveniles then gradually come to resemble adults, acquiring the complete adult plumage by their fourth year. Birds form permanent pairs that inhabit territories throughout the year. Their loud "goose-like" honking call is a familiar sound, particularly during the breeding season. They chose the tallest tree to nest, and even sometimes man-made pylons.

They feed on fish and sea snakes, which they catch by skimming over the water and catching their prey with their talons. They do not dive under water, however. They keep within 1km of shores, as there are no thermals over water.

Distribution and habitat A White Bellied Sea Eagle at the Territory Wildlife Park, Darwin

The White-bellied Sea-eagles are found in Australia, New Guinea, all of Southeast Asia, China and India. They are a common sight in coastal areas. Birds are often seen perched high in a tree, or soaring over waterways and adjacent land.

Conservation Status

The White-bellied Sea-eagles are listed as least concern by the IUCN. They are an estimated 10 to 100 thousands individuals, although there seems to be a decline in numbers.

Australia

White-bellied Sea-eagles are listed as marine and migratory under the Australian Environment Protection and Biodiversity Conservation Act 1999.

State of Victoria, Australia

• The White-bellied Sea-eagle is listed as threatened on the Victorian Flora and Fauna Guarantee Act (1988). Under this Act, an Action Statement for the recovery and future management of this species has been prepared.

• On the 2007 advisory list of threatened vertebrate fauna in Victoria, the White-bellied Sea-eagle is listed as vulnerable.

Food and feeding

The White-bellied Sea-eagle feeds mainly off aquatic animals, such as fish, turtles and sea snakes, but it takes birds and mammals as well. In the Bismarck Archipelago it has been reported feeding on various species of possum. It is a skilled hunter, and will attack prey up to the size of a swan. They also feed on carrion such as sheep and fish along the waterline. They harass smaller birds, forcing them to drop any food that they are carrying. Sea-eagles feed alone, in pairs or in family groups.

Nesting

It nests, usually close to other White-bellied Sea-eagles, in large nests in trees or on coastal cliffs. Normally two eggs are laid.

Gallery

Juvenile (first year)

Immature
(2nd or 3rd years)

Adult

Mature White-Bellied Sea Eagle over Adelaide River in Darwin

White-Bellied Sea Eagle (Adelaide River, Darwin)

White-Bellied Sea Eagle at the Territory Wildlife Park, Darwin

White-Bellied Sea Eagle at Corroboree near Darwin NT Australia